1. Technical Field
The present disclosure relates to voltage converters, and particularly to a voltage converter that is capable of conserving power.
2. Description of Related Art
Direct current to direct current (DC-to-DC) voltage converters are widely used. Referring to FIG. 2, a typical DC-to-DC voltage converter 10 generally includes a driver 11, a pulse width modulation (PWM) signal generator 12, a power supply 13, a first metal oxide semiconductor field effect transistor (MOSFET) Q11, a second MOSFET Q12, an inductor L11, and a capacitor C11. Both the PWM signal generator 12 and the power supply 13 are electrically connected to the driver 11. Both a gate of the first MOSFET Q11 and a gate of the second MOSFET Q12 are electrically connected to the driver 11. A source of the first MOSFET Q11 is electrically connected to a drain of the second MOSFET Q12, and a source of the second MOSFET Q12 is grounded. The inductor L11 is electrically connected between the source of the first MOSFET Q11 and the capacitor C11. The capacitor C11 is connected between the inductor L11 and ground.
When the voltage converter 10 is used, the power supply 13 provides a driving voltage V1 to the driver 11 to supply working power to the driver 11. A charging voltage V2 is applied to a drain of the first MOSFET Q11. The PWM signal generator 12 generates PWM signals and transmits the PWM signals to the driver 11. The driver 11 generates control signals in response to reception of the PWM signals and transmits the control signals to the gates of the first MOSFET Q11 and the second MOSFET Q12. The control signals control the first MOSFET Q11 and the second MOSFET Q12 to be alternately turned on and off. When the first MOSFET Q11 is turned on and the second MOSFET Q12 is turned off, the capacitor C11 is charged by the charging voltage V2. When the first MOSFET Q11 is turned off and the second MOSFET Q12 is turned on, the capacitor C11 is discharged through the inductor L11 and the second MOSFET Q12. In this way, an output voltage V3 is generated between the inductor L11 and the capacitor C11 and is used to supply working power to loads (not shown) of the voltage converter 10. Relative parameters of the output voltage V3, such as peak voltage value, pulse width, and period, can be regulated by means of changing pulse widths and periods of the pulse signals, inductance of the inductor L11, and capacitance of the capacitor C11.
However, in the voltage converter 10, the driving voltage V1 provided by the power supply 13 is generally invariable. When working current required by the loads of the voltage converter 10 decreases, the driving voltage V1 is unable to correspondingly decrease. Thus, power of the power supply 13 may be wasted, and the driving voltage V1 may become excessively high and damage the driver 11.
Therefore, there is room for improvement within the art.